Question

The ejection fraction will increase when: Group of answer choices End Systolic Volume (ESV) increases, End Diastolic Volume (EDV) increases, Heart rate increases, TPR increases

Answer 1

Answer is b) End diastolic volume increases.

Stroke volume is the amount of blood pumped by each ventricle per beat.

Ejection fraction is the fraction ( volume) of fluid ejected from chambers with each beat.

Increase in venous return increases end diastolic volume increasing the stroke volume and hence preload on heart.

Increase in preload increases the force of contraction as more blood has to be pumped effectively, so that extra amount of blood can be ejected to increase the stroke volume. Hence, option b) is incorrect.

Increase in end systolic volume decreases stroke volume, as increase in total peripheral resistance and vascular pressure increases afterload which increases end systolic volume and decreases stroke volume. Hence, option a), c) and d) are incorrect.